You could try posting on Godaven for temporary minyan requests. The logistics will be challenging, as even if you find 6 more, you won't want to be confined to staying in Reykjavik (for minyan) and only doing day trips from there, which will mean a lot of extra driving and backtracking (or missing the best stuff). I suppose you could try to coordinate lodging and stays with the other parties, but lodging along the Ring Road can be very difficult even just for your own family. Also figure out what you plan to do for maariv at that time.
